A hybrid-duplex system has been discussed that employs TDD (time-division duplex, which is a half-duplex technology) and FDD (frequency-division duplex, which is a full-duplex technology) at individual frequencies, wherein a TDD downlink is combined with an FDD line to increase capacity.
With regard to a hybrid FDD/TDD apparatus, it has been discussed that compatibility with an existing FDD terminal is maintained by a slot allocation method by which frequency bandwidths and time-slots are controlled depending on uplink/downlink traffic priorities.
A hybrid TDMA/FDMA/CDMA apparatus has also been discussed in which TDM is used for transmission from a BTS (base transceiver station) for downlink, and FDMA is used at the receiving end for uplink.
It has also been discussed with regard to a hybrid FDM (frequency division multiplex)/TDD system that each user connection is mapped onto basic channels in order of degrading transmission environment.    Patent Document 1: Japanese Laid-Open Patent Application No. 2005-341297    Patent Document 2: Japanese Laid-Open Patent Application No. 2006-54597    Patent Document 3: Japanese Laid-Open Patent Application No. 9-500512    Patent Document 4: Japanese Laid-Open Patent Application No. 2003-283507